Japanese Wax Scale
Egg -Ovoid and pale purple, the egg resembles purple pollen when shaken onto a white surface.
Crawler- Each crawler is flattened and tiny. In a mass, newly hatched crawlers appear rusty red.
Nymph-After molting, each scale secretes wax in tufts, forming a star.
Host Plants -Japanese wax scales have been reported on azalea, blueberry, camellia, Chinese elm, citrus, fig, eugenia, gumbo-limbo, Chinese holly, yaupon, jasmine, mulberry, pear, persimmon, plum, quince, sapodilla, Turks cap, and other plants.
Damage -A severe infestation of Japanese wax scale detracts from the host plant's appearance because of the many white scales and the copious honeydew that they excrete. A black fungus called sooty mold grows in the honeydew, further disfiguring the host plant.
Life History - Japanese wax scales begin to lay eggs in March, each scale laying from 1,000 to 2,000 eggs. By late May, tiny crawlers hatch and move about, searching for a place to feed. Feeding occurs along the twigs and leaf midribs of numerous woody plants. Once the crawlers insert their sucking mouthparts into the host plant, they are immovable. They then secrete the waxy covering from which they derive their name. The young scales mature throughout the summer, producing more waxy covering and becoming increasingly tolerant to pesticides. They overwinter as adults.
Handpicking scales in winter (if practical) is an effective control measure. Since they may lay their eggs apart from their host plants, the scales should be destroyed after removal. The Japanese wax scale seems to be one of the most difficult ornamental plant pests to control. However because there is only one generation per year, applying pesticides to the crawler stage in early June will give virtually complete control. Applications of any pesticide must be repeated because the crawlers emerge from the female's protective wax coating for 2 or 3 weeks and because recommended pesticides grow ineffective in the environment. For specific controls, see the current state extension service recommendations.